Method and moulding devices for moulding three-dimensional products

ABSTRACT

The invention provides a method for moulding three-dimensional products from a mass of foodstuff starting materials which are suitable for consumption, in particular a meal mass. The method comprises the steps of filling a mould cavity, which is open on one side. with the mass of foodstuff starting materials which arc suitable for consumption. which mould cavity is defined by a boundary comprising walls and base, in order to mould a moulded three-dimensional product, and the removal of the moulded three-dimensional product from the mould cavity. In the method according to the invention, during removal the adhesion forces between the moulded product and the boundary are eliminated virtually simultaneously along all the interfaces.

BACKGROUND OF THE INVENTION

This application is a continuation of U.S. patent application Ser. No.13/748,282, filed Jan. 23, 2013, which is a continuation of U.S. Pat.No. 8,371,836, filed Jul. 8, 2011, which is a divisional of U.S. Pat.No. 7,976,303, filed Dec. 23, 2004, which is a National Stage ofInternational Application No. PCT/NL03/00470, filed Jun. 26, 2003, whichclaims priority to Application No. NL1020942, filed Jun. 26, 2002. Thecontents of all these applications are hereby incorporated by referencein their entireties.

The invention relates in general to the moulding of three-dimensionalproducts from a mass of foodstuff starting materials which are suitablefor consumption, in particular from a meat mass. More specifically, theinvention relates to a moulding method, moulding devices and componentswhich can be used in moulding devices.

SUMMARY OF THE INVENTION

A first aspect of the invention relates to a method for mouldingthree-dimensional products from a mass of foodstuff starting materialswhich are suitable for consumption, in particular a meat mass,comprising the steps of a) filling a mould cavity, which is open on oneside, with the mass of foodstuff starting materials which are suitablefor consumption, which mould cavity is defined by a boundary comprisingwalls and base, in order to mould a moulded three-dimensional product ;and b) removing the moulded three-dimensional product from the mouldcavity.

A method of this type and a device used for the method are known in theart, for example from the international patent application WO-A-00/30458in the name of the Applicant and can be used to mould edible productsfrom, for example, kneaded meat. This known device of theso-called“rotating drum type” has a rotatable drum which is drivencontinuously by an associated drive. A plurality of mould cavities whichdefine the shape of the products which are to be produced are located onthe outer side of the drum. At the filling position there is a fillingmember which fills the mould cavities which move past it during rotationwith the mass. The products formed in this way are removed from themould cavities at a release position located downstream of the fillingposition. This known moulding device uses means for exerting fixingpressure which are designed to exert a fixing pressure which acts on themass in the mould cavity after the filled mould cavity has been closed.This fixing pressure differs from the filling pressure, which is exertedon a portion of the mass during filling of a mould cavity with thisportion. The fixing pressure is used to make the pieces of the massstick together after the filling operation and in this way to obtain adimensionally stable product of the desired end weight which can beremoved from the mould cavity.

In addition, this application describes a number of techniques used toassist with the removal of moulded products from the mould cavities inquestion under the influence of the force of gravity. In one embodiment,during each revolution of the drum a web of a film is placed in a mouldcavity. For removal, stress is imparted to the web from one side, sothat the web and therefore the moulded product are lifted out of themould cavity from one side. If appropriate, the removal can be furtherassisted by compressed air being blown in beneath the web from a centralpoint located in the base of the mould cavity. In another embodiment, aflexible membrane is secured in a mould cavity in order to preventcontamination. The base of the mould cavity is in communication with anair source and/or vacuum means at various locations, via passages. Byselective actuation, it is possible for the flexible membrane to besucked into the mould cavity or for a moulded product to be removed. Inthis embodiment too, the removal can be assisted by compressed air whichis blown onto the underside of the membrane from a central location andfrom points located in the vicinity of the peripheral edge of the base.

Now, it has been found that the shape of the moulded product isinsufficiently uniform, in particular their edge definition.

This leads to product loss. Defects which have been observed include theformation of lips, small pieces which break off at the edges, dents andthe like.

Furthermore, it has been found that the service life of the plasticfilms used leaves something to be desired. The service life is short,meaning that they have to be replaced frequently, with all theassociated drawbacks relating to production idle time, maintenance workand other costs.

A further drawback of these known techniques is that it is difficult tomonitor and maintain hygiene in these devices on account of the numberof parts which come into contact with foodstuff starting material.

It is an object of the present invention to provide a method and deviceswith which it is possible to provide products with a shape which is moreuniform over the course of time. Another object of the invention is toprovide a method and devices which can be used to produce products witha low spread in weight. Yet another object of the invention is toprovide such a method and device in which the number of components whichcome into contact with the foodstuff starting material is very small.

In the method according to the invention, to this end step b) comprisesthe removal of the adhesion forces between product and boundary of thecavity substantially simultaneously at all the interfaces between themoulded three-dimensional product and the boundary. According to theinvention, the adhesion forces are substantially eliminated, at the timeof release, at all the surfaces of the moulded product which are incontact with the base and peripheral wall simultaneously. It has beenfound that the removal of a moulded product is simpler and leads to lessproduction loss if the adhesion forces are eliminated on all sides(apart from the open side of the mould cavity). The release occurspartly as a result of the force of gravity (the inherent weight of amoulded product), with a force of this nature simultaneously beingboosted by eliminating the adhesion forces on all sides. As a result ofrelease occurring on all sides simultaneously, the edge definition ofthe moulded product is greatly improved compared to the prior art, andthe finished moulded product more accurately corresponds to the mouldcavity, since it retains the shape. It should be emphasized that in theinvention, in addition to the force of gravity a force is temporarilyalso exerted for the purpose of removing the moulded product from amould cavity, which force is not produced by mechanical means which arein contact with the product, such as for example a plunger. Furthermore,this additional expulsion force is generated at the time of release andis not permanently present, as for example in the case of a non-sticklayer. The reproducibility of the shape of the moulded products in thedevice according to this aspect of the invention is improved in thisway, as is the reproducibility of the weight. In addition, there is noneed for any additional materials, such as the disposable film used inthe moulding device according to the prior art, or for the associatedprocessing equipment.

A means for eliminating the adhesion forces is advantageously used toremove the adhesion forces. In this context, use is made of thedifferences in properties of the means which eliminates the adhesionforces and those of the foodstuff starting material from which theproduct is moulded. The preferred examples of this means comprise aforcing fluid (a pressurized fluid), an optionally permanent coating ofthe boundary with a coating material whose action of eliminatingadhesion forces can be activated, for example by applying anelectrostatic charge, by bringing about a change in the state ofaggregation, for example from solid to liquid or liquid to gaseous, forexample converting a film of water into steam by heating, or by theinitiation of a chemical reaction, in which case opposing forces aregenerated or the inherent adhesion properties are reduced, or avisco-elastic substance whose action is dependent on the fillingpressure and time used. Combinations of these measures are alsopossible.

It is more preferable to use a forcing fluid, in particular compressedair or steam. Combinations of compressed air in which a liquidconstituent is dispersed, such as water, for humidification, can also beused. Moreover, this opens up the possibility of implementing a desiredaddition, if necessary, to the product, for example a (preserving) saltdissolved in water, or oil, etc. The boundary is permeable in order toallow the supply of a forcing fluid of this type.

For a forcing fluid to be supplied on all sides (apart from the open topside), it is advantageous for the boundary of a mould cavity to beprovided with passages with openings which, distributed over base andperipheral wall of the mould cavity, open out at the surface of theboundary, with a pressurized fluid being fed to the passages. Thepassages may be of any desired shape, rectilinear, angled or curved, maybe regular or irregular, taper or may widen out at their end. The shapeand size of the passages partly determine the depth of penetration ofthe mass into the boundary and the through-flow of the fluid in theboundary, and therefore the forces exerted by the fluid.

In addition, it is preferable for the size of the outlet openings of thepassages to be selected in such a way that the pieces of the foodstuffstarting material are not caught in the passages. This will be explainedin more detail below. Examples of a material used for this type ofboundary include a perforated plate or a foil provided with openings,for example made from nickel or stainless steel. Passages can be formed,for example, using a laser treatment. Etching or electroforming areother examples of suitable production techniques.

A particularly preferred boundary comprises a porous structure ofintercommunicating pores. In this way, it is possible to obtain auniform distribution of the forcing fluid over all the interfacesbetween the boundary and the moulded product, which assists with theuniform removal of the product. The pore size will be selected as afunction of the starting material to be processed and the forcing fluidused. By way of example, it has been found that in the case of porousboundaries made from sintered stainless steel with effective porediameters in the range from approximately 1-20 micrometers, effectiveremoval can be achieved for a specific meat mass. Combinations ofpassage structures and porous structures are also among the possibleoptions.

Examples of suitable materials for the porous structure of the boundaryinclude ceramic materials, plastics and metals, including in particularsintered steel.

It should be noted that the patent publications U.S. Pat. No. 4,987,643and U.S. Pat. No. 4,212,609 have per se disclosed moulding machines inwhich the mould cavities have a base which can move up and down forremoval of moulded products, which base is porous and is incommunication with a supply of compressed air or the like to assist withremoval of the moulded products from the mould cavities.

The mould cavities are advantageously formed in the porous boundary byspark erosion. The production of a mould from porous metal often uses atreatment which causes the openings of the pores which open out at thesurface to be virtually completely closed up. Spark erosion causes theporous structure of the boundary to be opened up again at the locationof the mould cavity.

After use, the passages and/or openings can also be used for cleaning ofthe mould cavities, for example by water or steam, optionally with theaddition of a cleaning agent or disinfectant, being fed to them.

According to a further preferred embodiment, during step a) air which isenclosed between the mass and the boundary is discharged through theboundary. The boundary structure with passages and/or pores is eminentlysuitable for this purpose.

Complete filling of a mould cavity is achieved by removing this air, forexample sucking it out with the aid of suction means, so that theenclosed air does not leave any traces in the shape of the finishedproduct or interferes with uniform removal.

According to a second aspect, the invention relates to a device formoulding three-dimensional products from a mass of foodstuff startingmaterials which are suitable for consumption, in particular a meat mass,comprising a moulding surface, which is provided on one side with one ormore mould cavities which are open on one side and are defined by aboundary comprising walls and base, a mass feed member, which isarranged at a mass feed position, for feeding the said mass to the mouldcavities.

A device of this type, in which the moulding surface is the outer wallof a drum, is known from the abovementioned WO publication WO 00/30458.

According to the invention, the device also comprises means forsimultaneously removing the adhesion forces between product and boundaryof the mould cavity at all interfaces between a mouldedthree-dimensional product and the boundary. A device of this typeachieves the above-described advantages relating to edge definition anduniformity of shape and weight of the moulded products.

The said means will be selected as a function of the embodiment inquestion.

If a forcing fluid is used as the means which eliminates the adhesionforces, the said means comprise excess-pressure means which are in fluidcommunication with the boundary of a mould cavity and are used to supplya pressurized fluid, such as compressed air or water. For a uniformdistribution of the forcing fluid, it is advantageous for the boundaryto be provided with passages with openings, which passages are incommunication with excess-pressure means. More preferably, the boundarycomprises a porous structure of intercommunicating pores, for thereasons outlined above.

According to another preferred embodiment, the said means form anoptionally permanent coating of the mould cavity, as explained above inconnection with the method according to the invention.

In yet another preferred embodiment, the device also comprisesreduced-pressure means for forming reduced pressure in a mould cavityduring the filling operation, so that enclosed air can be sucked out.

To obtain a simple structure of the device, in particular the system oflines used to supply a pressurized fluid or remove air, it isadvantageous for a connecting passage to be in communication with theboundary of a mould cavity, which connecting passage can be selectivelycoupled to the reduced-pressure means and the excess-pressure means.

The moulding surface is advantageously made completely from sinteredmetal in which the mould cavities are formed by spark erosion. Asingle-piece moulding surface is a component which is easier to exchangewhen the moulding device needs to be used for the production of adifferent product shape or when the moulding device is presented formaintenance, such as cleaning, or for repair.

With a view to product flexibility, it is advantageous for the mouldingsurface to be provided with recesses in which corresponding inserts arereleasably accommodated, these inserts comprising the mould cavities. Inan embodiment of this type, the inserts are exchangeable, so that avariety of products can be moulded using the same moulding surface.

The recesses are advantageously substantially rectangular in shape, andif the outer wall of a drum is the moulding surface, the insertscomprise a substantially corresponding rectangular body, of which onlythe upper surface, in which the mould cavity is located, has a radius ofcurvature matching the radius of curvature of the drum. Recesses of thisform are relatively easy to manufacture into the drum, and thecorresponding inserts can also be produced in a simple way.

In a further advantageous embodiment thereof, the height of an insert isslightly smaller than the depth of the recess, and spacers are providedbetween the base of the recess and the underside of the insert, so thatthere is a space which can function as a collection chamber forextracted air or distribution chamber for a forcing fluid. Obviously, itis also possible for the spacers to form an integral part of theinserts, for example in the form of small legs.

The method described above can be carried out with various types ofmoulding devices, for example a turntable, a turret, a drum or anoptionally stationary flat plate.

With a view to achieving a high production rate, the moulding surface ispreferably the wall of a drum which can be rotated in a direction ofrotation by associated drive means and is provided with at least onemould cavity which is open at the outer circumference of the drum andhas an associated boundary comprising walls and base.

According to a third aspect, the invention relates to a moulding surfacefor moulding three-dimensional products, in particular a moulding drum,from a mass of foodstuff starting materials which are suitable forconsumption, in particular from a meat mass, provided on one side withone or more mould cavities which are open on one side and are defined bya boundary comprising walls and base. A moulding surface of this type inthe form of a drum is known from WO-A-00/30458, as discussed above.According to the invention, the walls and base which form the boundaryare provided with holes which extend through the boundary. A mouldingsurface of this type allows the adhesion forces between the boundary anda moulded product to be removed virtually simultaneously at all theinterfaces, for example using a forcing fluid as has also been explainedabove. This leads to the abovementioned advantages with regards tosimplicity and ease of removal and reduced product wastage. Furthermore,this leads to more rapid removal, so that a higher production rate canbe achieved.

The moulding surface is advantageously a moulding drum. A drum of thistype has a substantially cylindrical drum wall. The drum diameter is,for example, 0.15 to 0.7 m, while the length may vary from a few tens ofcentimetres, for example 30 cm, to a few metres. The drum may be madefrom a single piece, such as for example a pipe, or from a plurality ofinterconnected pipe sections, reinforcements being provided if desired,for example ribs, plates or prestressing means. The mould cavities areprovided in the outer side of the drum wall, for example in the form ofrows which are parallel in the axial direction or offset. Other examplesof moulding surfaces are straight plates, a turntable or a turret.

The holes advantageously have a shape and/or dimensions which are suchthat the mass is subject to sufficient resistance for it not topenetrate deeply into the holes as a result of the filling pressureapplied to the mass, which can generally be regarded as a visco-elasticmaterial, during the filling operation. Since the filling pressure isonly applied for a short time during filling, given sufficientresistance the mass will only be deformed slightly and will only be ableto penetrate into the holes to a slight extent. If the mass penetratesrelatively deeply into the holes, there is a risk of the mass or piecesof it being caught in the holes during removal. This risk can be avoidedin accordance with the invention. Irregular, angular or curved holes areexamples of suitable shapes, since they provide a sufficiently greatcounterpressure to the mass during filling. Holes with relatively smallopenings at the surface of the boundary which defines the mould cavityalso offer a resistance of this nature.

One example is holes which taper towards the said boundary surface. Inaddition, shaping and/or dimensioning the holes in this way has theadvantage that the forcing means, which can generally flow to a greaterextent than the mass of starting material, exerts expulsion pressure onthe mass via all the holes during the removal operation and scarcelyescapes along those holes where the mass may already have been released.The shape and/or dimensions of the holes are advantageously selected asa function of the rheological properties of the starting material andthe forcing means used.

In a preferred embodiment, the holes or passages with openings open outin the mould cavity. The openings may be distributed regularly orirregularly over the base and wall. By way of example, it is possiblefor the number of passages in the vicinity of the transition from thebase to the wall to differ from, for example be greater than, the numberof passages in the remaining surface of these walls and base.

In another preferred embodiment, the holes comprise a porous structureof intercommunicating pores. An embodiment of this type allows a uniformdistribution of the holes over the boundary and therefore allows uniformremoval of a moulded product from the mould cavity.

As has already been described above, a boundary is advantageously madefrom sintered metal, more particularly by means of spark erosion. Themoulding surface is advantageously made from a porous sintered metal, ofwhich the pore openings which open out at the surfaces are sealed off bythe machining steps carried out during production of the mouldingsurface, after which the mould cavities are manufactured by sparkerosion, so that the pore openings are locally opened up again.

In a further preferred embodiment, the moulding surface with the mouldcavities therein is produced from one piece, more particularly havingsimilarly shaped mould cavities. A moulding surface of this type can beexchanged quickly and easily, for example if a product change is to becarried out, compared to a moulding surface with moulding elements whichcan be exchanged separately and have one or more mould cavities, witheach moulding element having to be changed separately, requiring a largenumber of operations. This relatively high exchange speed reduces thetime required for maintenance, repair or changeover, so that the idletime of the moulding device in which the moulding surface is used can bekept short.

The invention also relates to an assembly of at least two mouldingsurfaces for moulding three-dimensional products, in particular mouldingdrums according to the invention, in which the shape of the mouldcavities in one moulding surface is identical and is different from theshape of the mould cavities in another moulding surface. As has beenexplained above, moulding surfaces of this type can be exchanged quicklyand easily.

Other advantageous embodiments of a moulding surface according to theinvention have already been discussed above in connection with the firsttwo aspects of the invention.

According to a further aspect, the invention relates to a mouldingdevice for moulding three-dimensional products from a mass of foodstuffstarting materials which are suitable for consumption, comprising a drumwhich can be rotated in a direction of rotation by associated drivemeans and has a drum wall which is provided with mould cavities whichare open on the outer circumference of the drum and are delimited by aboundary comprising walls and base, a mass feed member, which isarranged at a mass feed position along the outer circumference of thedrum, for supplying the said mass to the mould cavities, andreduced-pressure means for forming a reduced pressure in the mouldcavities.

A moulding device of this type is known from the abovementionedinternational patent application WO-A-00/30458 in the name of theApplicant and can be used to mould edible products from, for example,kneaded meat. This known device of the so-called “rotating drum type”hasa rotatable drum which is driven continuously by an associated drive. Onthe outer side of the. drum there are a plurality of mould cavitieswhich determine the shape of the product which is to be produced. At afilling position there is a filling member which fills the mouldcavities which move past it during rotation with the mass. The productswhich have been moulded in this way are removed from the mould cavitiesat a release position located downstream of the filling position. Thisknown moulding device uses means which exert a fixing pressure and aredesigned to exert a fixing pressure which acts on the mass in the mouldcavity after the filled mould cavity has been closed. This fixingpressure is distinct from the filling pressure which is exerted on aportion of the mass during the operation of filling a mould cavity withthis portion. The fixing pressure is used to make the pieces of the massadhere together after the filling operation and in this way to obtain adimensionally stable product of the desired end weight which can beremoved from the mould cavity.

In one embodiment of this known device, which is described inWO-A-00/30458, a strip of elastically deformable (plastics) materialbears against the outer circumference of the drum from an applicationposition located upstream of the filling member to a release position ofthe product at the underside of the drum. This strip has the function ofcovering the base and side walls of the mould cavities and passageopenings provided therein, so that they do not come into direct contactwith the mass. By generating reduced pressure, the strip is sucked intothe mould cavities, onto the walls and base thereof. After the load hasbeen relieved, the strip returns to its original form, so that theproducts can be released from the strip by guiding the strip upwards atan acute angle. As a result, the products drop off the strip, sincethese products are not able to follow this sudden change in direction ofthe strip.

However, it has been found that the service life of the plastic filmsused leaves something to be desired. The service life is short, andconsequently the films have to be replaced frequently, with all theassociated drawbacks with regard to idle time, maintenance work andother costs.

Furthermore, it has been found that the edge definition of the mouldedproducts is not always sufficient, which can lead to product loss.

In addition, the release from the mould cavities is not alwayssatisfactory, which likewise has an adverse effect on the quality of themoulded products.

According to this aspect, the present invention is based on the broadobject of improving the abovementioned shortcomings. More particularly,it is an object of the invention to provide a moulding device forproviding edible, three-dimensional products with a considerable stripservice life. In addition, it is an object of the invention to provide amoulding device which can be used to produce products of the desiredshape. It is also an object of the invention to provide a mouldingdevice from which products can be released effectively.

According to this aspect, the invention provides a moulding device ofthe type described in the preamble, in which around the outercircumference of the drum there is a strip, the strip being provided, atthe location of a mould cavity, with a flexible premould whichsubstantially corresponds to the mould cavity. In this moulding deviceaccording to the invention, there is a strip wrapped around the drum,preferably made from a plastics material, in which there areprefabricated flexible premoulds at the location of the mould cavities.Since the premoulds, the shape of which is virtually identical to thatof the corresponding mould cavities, are formed in the strip prior tooperation, these premoulds can be sucked into the mould cavities withthe aid of the reduced-pressure means more quickly and more easily thanin the case of the strip according to the prior art, which in each casereturns to its original, planar shape and is continuously renewed.

The ends of the web from which the strip is formed can be fixed to thedrum using adhesive tape, glue, mechanical securing means or the like.The ends can also be secured to one another, for example by hot-welding,so that an endless strip is formed.

It is preferable for there also to be excess-pressure means which are incommunication with the mould cavity and are designed to feed a pressuremedium to a mould cavity. When a pressurized medium, for examplecompressed air, is fed to the mould cavity between, on the one hand, thebase and walls thereof and, on the other hand, the underside of theflexible premould, the premould together with the moulded product ispushed out of the mould cavity, so that it is possible to simplify therelease of the moulded product.

To ensure that during the fluctuating load on the strip as a result ofthe flexible premoulds being repeatedly sucked in and expelled the stripis not pushed off the drum, the flexibility of the premoulds ispreferably greater than the flexibility of the surrounding part of thestrip. The relatively rigid part of the strip is held taut around thedrum, while the premoulds are sufficiently flexible to adapt to thevarying pressure conditions.

In order to maintain the correct positioning of the strip on the drum,in particular the flexible premoulds with respect to the mould cavities,during operation, the strip advantageously has a sandwich structurewhich comprises a layer with flexible premoulds from a first plasticsmaterial and a layer with openings in it, the periphery of whichopenings substantially corresponds to that of the flexible premoulds,made from a second plastics material with a higher rigidity than thefirst plastics material.

A thermoplastic elastomer is advantageously used for the first plasticsmaterials of the layer with flexible premoulds. The second plasticsmaterial may, for example, be polystyrene. In general, the secondplastics material will be positioned on the drum side.

The premoulds can therefore be produced by preheating to above thesoftening point of the thermoplastic and deformation, followed bycooling, while the elastic properties ensure that the premoulds can bearin the correct position against the walls and base of the mould cavity.If the drum itself can be heated, it can be used, starting from a flatstrip, to form the premoulds therein on a one-off basis prior to thefilling operation, in the manner described above. An example of asuitable thermoplastic elastomer is SEBS.

The premoulds are advantageously formed in a planar strip bythermoforming. Premoulds formed in this way produce products with ahigher edge definition compared to the prior art during moulding.

In order to increase the service life of the strip still further, at theouter periphery the strip is preferably protected by a protective stripmade from wear-resistant material in which openings are provided, theperiphery of which substantially corresponds to the periphery of themould cavities in the drum. Since, during the filling operation, thestrip with premoulds frequently comes into contact with the mass feedmember past which the drum with strip rotates in a sealing manner with aview to preventing loss of starting materials, wear occurs as a resultof the friction between mass feed member and strip. A thin flexiblestrip made from a metal or metal alloy, for example spring steel,provides the required wear resistance and in this way protects theplastic strip below. The ends of the protective strip can be attached toone another or to the drum in a suitable way, for example using hooks ora cam.

The invention also relates to a strip which is clearly intended for theabovementioned moulding device with at least one mould cavity accordingto the invention, which strip is provided, at a position correspondingto a mould cavity of the moulding device, with a flexible premould whichsubstantially corresponds to the mould cavity. Preferred embodiments ofthis strip, as discussed above, are defined in the correspondingsubclaims.

Furthermore, the invention relates to an assembly of a strip accordingto the invention of this type and a protective strip made fromwear-resistant material in which there are openings, the periphery ofwhich substantially corresponds to the periphery of the premoulds in thestrip.

According to yet another aspect, the invention relates to a mouldingdevice for moulding three-dimensional products from a mass of foodstuffstarting materials which are suitable for consumption, comprising a drumwhich can be rotated in a direction of rotation by associated drivemeans and has a drum wall which is provided with mould cavities whichare open at the outer circumference of the drum and are defined by aboundary comprising walls and a base ; a mass feed member, which isarranged at a mass feed position along the outer circumference of thedrum, for feeding the said mass to the mould cavities; andreduced-pressure means for forming a reduced pressure in the mouldcavities.

A moulding device of this type is known from the international patentapplication WO-A-00/30458 in the name of the Applicant and can be usedfor the moulding of edible products made, for example, from kneadedmeat. This known device, of the so-called “rotating drum type”, has arotatable drum which is driven continuously by an associated drive. Onthe outer side of the drum there are a plurality of mould cavities whichdetermine the shape of the product which is to be produced. A fillingmember is arranged at a filling position and fills the mould cavitieswhich move past it during rotation with the mass. At a release positionlocated downstream of the filling position, the products formed in thisway are removed from the mould cavities.

In this known moulding device, means for exerting fixing pressure, whichare designed to exert a fixing pressure on the mass in the mould cavityafter the filled mould cavity has been closed, are used. This fixingpressure is distinct from the filling pressure which is exerted on aportion of the mass while a mould cavity is being filled with thisportion. The fixing pressure is used to make the small pieces of themass adhere together after the filling operation and in this way toobtain a dimensionally stable product which can be removed from themould cavity.

In one of the embodiments of the known device, which are described inWO-A-00/30458, exchangeable moulds, for example made from metal or rigidplastic, with a mould cavity therein, are secured in the drum wall. Toprevent contamination, a shape-restoring flexible membrane is arrangedin the mould cavity. The base of the mould cavity is in communicationwith an air source and/or vacuum means via passages at variouslocations. By selective actuation, the flexible membrane can be suckedinto the mould cavity or a moulded product can be removed.

Now, it has been found that it is difficult to exert a fixing pressureon the portion of the mass which has been introduced into a mouldcavity, yet in a plurality of cases this operation is actuallysuperfluous. Furthermore, it has been found that during operation, insome cases it is impossible to fill the entire mould cavity, andconsequently the moulded products lack uniformity of shape and weight.

This aspect of the present invention is based on the general object ofalleviating the abovementioned shortcomings. More particularly, it is anobject of the invention to provide amoulding device for providingthree-dimensional products from an edible mass, which moulded productshave a uniform appearance and shape and an equal weight (withinacceptable tolerances).

According to this aspect of the invention, in the case of the mouldingdevice of the type described in the introduction, the boundary is atleast in part provided with a large number of fine openings which are incommunication with the reduced-pressure means.

In this moulding device according to the invention, the base and/or sidewalls, which together form the boundary of the mould cavity, comprise alarge number of openings. The dimensions of these openings are such thatno or scarcely any solid pieces of the mass of foodstuff startingmaterials can pass through them.

These openings are connected to reduced-pressure means for generating areduced pressure in the mould cavity during the filling operation. Onaccount of the fact that air is sucked out of the mould cavity over arelatively large area and through a large number of openings compared tothe local suction nozzles in accordance with the prior art, it isimpossible for any air to be included during the filling of the mass.This inclusion of air is considered to be one of the possible causes ofthe non-uniform shape and variation in weight of the products inaccordance with the above-described embodiment of WO 00/30458.

The reproducibility of the shape of the moulded products is improvedwith the device according to this aspect of the invention in this way,as is the reproducibility of the weight.

In addition, there is no need for any additional materials, such as thedisposable film used in the moulding device according to this prior art,or for the associated processing equipment.

Examples of a material for this boundary comprise a perforated plate oran electroformed foil provided with openings, for example made fromnickel or stainless steel.

In a preferred embodiment, the boundary comprises a porous structure ofintercommunicating pores. A structure of this type, of which preferablythe entire boundary of the mould cavity is composed, more preferablyproduced as a single unit, is permeable to gas or other fluid but is notpermeable or is scarcely permeable to the small particles of the mass. Apore structure of this type allows the air to be sucked out of the mouldcavity in a very uniform way, resulting in products with an even moreuniform quality in terms of shape and weight.

It should be noted that moulding machines in which the mould cavitieshave a base which can move up and down in order to release mouldedproducts, which base is porous and is in communication with a feed ofcompressed air or the like in order to assist with the release of themoulded products from the mould cavities, are known per se from patentpublications U.S. Pat. No. 4,987,643 and U.S. Pat. No. 4,212,609.

Examples of suitable materials for the porous structure of the boundaryinclude ceramic materials, plastics and metals, including in particularsintered steel.

According to a further preferred embodiment, the outer circumference ofthe drum is provided with recesses in which corresponding inserts areremovably accommodated, which inserts comprise the mould cavities. In anembodiment of this type, the inserts are exchangeable, and consequentlythe changeover times from one product to another are relatively short,since the exchange of mould cavities required for this purpose can becarried out quickly and easily.

The recesses are advantageously substantially rectangular in shape, andthe inserts advantageously comprise a substantially matching rectangularbody, of which only the upper surface, in which the mould cavity islocated, has a radius of curvature matching the radius of curvature ofthe drum. Recesses of this form are relatively easy to form in the drumand it is also easy to produce the associated inserts.

In a further expedient embodiment thereof, the height of an insert isslightly less than the depth of the recess, and spacers are providedbetween the base of the recess and the underside of the insert, so thatthere is a space which can function as a collection chamber ordistribution chamber for air. Obviously, the spacers may also form anintegral part of the inserts, for example in the form of small legs.

The openings of the boundary are advantageously also in communicationwith excess-pressure means which are designed to supply a pressuremedium to the mould cavity, so that the release of products from themould cavities as a result of their inherent weight can be assisted by asuitable pressure medium being passed through the fine openings from theinside outwards, so that the product is in this way pushed out of themould cavity. Moreover, this opens up the option of carrying out adesired addition, if necessary, to the product, for example water oroil, etc. In this way, after use, it is also possible for the device, inparticular its mould cavities, to be cleaned by rinsing with a cleaningagent.

In the base of the recess there are advantageously one or more openingswhich can be used for a number of purposes. It is preferable for aconnecting passage to be in communication with the opening in the baseof the recess, which connecting passage can be selectively connected tothe reduced-pressure means and the excess-pressure means.

If desired, a release device, arranged at a release position, can beprovided for removal of moulded products from the mould cavities. Arelease device of this type is useful primarily for the moulding devicewith flexible premoulds if the moulded products have a considerabletendency to stick to the flexible premoulds. The release device isdesigned in such a way that it has a separation element which can beintroduced between the flexible premould and the moulded product withoutdamaging either of them.

A preferred embodiment of a release device of this type comprisesdriveable endless conveyors which are arranged in parallel and describea movement path about turning elements, between which conveyors thereare connecting elements, in such a manner that the connecting elements,at the release position, pass virtually through the centre of the axisof the turning element in question. In this preferred embodiment, withthis turning element, for example a turning roll or gearwheel, themovement path of the connecting elements is suddenly reversed at therelease position. As a result of this reversal position being locatedalong a tangent on the drum, in particular along the tangent on anejected flexible premould, at a location where a moulded product movesout of the premould slightly as a result of its own weight, and as aresult of the direction of movement being selected to be opposite to thetangential direction of movement of the drum, it is possible to achieveeffective release. The connecting elements have a small surface area, sothat the removed products do not stick to them, but rather can drop offonto a discharge belt which is guided along the bottom of the releasedevice.

In an expedient embodiment of a release device of this type, the endlessconveyors comprise chains, the links of which comprise an inwardlyprojecting part to which transverse spindles are connected.

It will be understood that a release device of this type can also beused for other applications, for example as what is known as a shooterbelt for putting objects down in a metered manner onto another conveyorbelt or onto positions where there is little space, and also in otherknown moulding devices.

The drum made, for example, from plastics or (sintered) metal—which maybe solid or hollow—and is used in the preferred embodiments of themoulding devices according to the invention is difficult to produce witha constant diameter. This means that leakage may occur between the massfeed member and the outer circumference of the drum, which isundesirable with regard to loss of starting material but also on accountof a resultant reduction in the quality of the moulded product.

To avoid this problem, the mass feed member advantageously comprises ahousing in which there is a through-passage for mass to pass from aninlet to an outlet located on the drum side, the drum side bearing in asealing manner against the drum and being designed to adapt toirregularities in the outer circumference of the drum. This ensures thatthe mass feed member, also known as the filling shoe, bears in a sealingmanner against the drum, even when the drum is not perfectlycylindrical, so that loss of mass is limited and leakage during theapplication of a vacuum and/or pressure is avoided. For this purpose,the drum side of the filling shoe is flexible to a certain degree, sothat it is able to follow any deviations.

In an appropriate embodiment, the drum side of the mass feed membercomprises a flexible plate which is held against the outer circumferenceof the drum under pressure produced by excess-pressure means. A suitablematerial for the flexible plate is Teflon, which in addition to therequired sealing action also imparts resistance to wear. According to afurther preferred embodiment, the excess-pressure means comprise atleast one pressure cushion, a number of lamellae, which are positionedtransversely with respect to the direction of rotation of the drum,being arranged between the pressure cushion and the plate. Theselamellae provide lines with a high rigidity in the axial direction ofthe drum, while the plate is able to follow deviations in the diameterof the drum. To further limit loss of mass resulting from the continuoussupply, the drum side of the mass feed member, as seen in thecircumferential direction of the drum, extends on either side of theoutlet, over a distance which covers at least one mould cavity. If themass feed member is operating continuously, it is if desired possible toprovide a diverter passage, for example in the flexible plate, which onone side is in communication with the through-passage and on the otherside is in communication with an outlet opening at a position, upstreamof the outlet of the through-passage, where the next mould cavity to befilled is located. If there is no mould cavity in front of the outletopening of the mass feed member, a partial stream of the mass istherefore introduced into the next mould cavity which is to be filled,until the latter can be filled via the ordinary outlet from thethrough-passage.

In order to enable the mass feed member to be used for various types offoodstuff starting material, including masses which include tough(muscle) fibres, it is advantageous for a cutting device to be providedin the through-passage on the drum side, preferably at the downstreamedge of the through-passage, as seen in the direction of rotation.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be understood that the abovementioned mass feed member is alsosuitable for use in moulding devices with a rotating moulding drum,other than the embodiments discussed above.

The invention is explained below with reference to the appended drawing,in which:

FIG. 1 shows a perspective view of an embodiment of a moulding device ofthe invention;

FIG. 2 shows a side view of the embodiment shown in FIG. 1;

FIG. 3 shows an exploded perspective view of an embodiment of a mouldingdevice with insert;

FIG. 4 shows a view of an embodiment of an insert with mould cavity;

FIG. 5 shows a cross section through an embodiment of a moulding deviceaccording to the invention, illustrating its operation;

FIG. 6 shows a detail of the embodiment shown in FIG. 5;

FIG. 7 shows another embodiment of a moulding device in accordance withthe invention;

FIG. 8 shows an embodiment of a moulding device with release device inaccordance with the invention;

FIG. 9 shows the release device presented in FIG. 8 in more detail;

FIG. 10 shows the operation of the release device illustrated in FIG. 8;

FIG. 11 diagrammatically depicts an embodiment of a moulding device withmass feed device in accordance with the invention;

FIG. 12 shows a detail of the mass feed device shown in FIG. 11;

FIG. 13 illustrates the operation of the mass feed device;

FIG. 14-15 show diagrammatic cross sections through various embodimentsof a mould cavity with associated boundary;

FIG. 16-17 show detailed structures of various pore forms of a boundaryof a mould cavity;

FIG. 18 shows a detailed view of an embodiment of a boundary of a mouldcavity with a passage structure;

FIG. 19 diagrammatically depicts an embodiment of the method accordingto the invention;

FIG. 20 diagrammatically depicts another embodiment of the methodaccording to the invention; and

FIG. 21-23 show various embodiments of a moulding surface according tothe invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 diagrammatically depicts a perspective view of an embodiment of amoulding device 10 according to the invention, while FIG. 2 shows a sideview of this device.

The moulding device 10 comprises a frame 14 which can be moved with theaid of wheels 12. A moulding drum 16 is mounted on the frame 14 in sucha manner that it can be rotated about a horizontal axis and is coupledto a drive, for example an electric motor. The moulding drum 16comprises mould cavities, which are not visible in FIGS. 1 and 2. A massfeed member 18 for feeding mass which is to be moulded to the mouldcavities of the moulding drum comes into close contact with the outercircumference of the moulding drum 16. The mass is fed from adisplaceable storage device 19 with introduction funnel 20 and then viaa releasable connecting pipe 22 to the mass feed member 18 by means ofan (optionally continuously) operating pump (not shown). In the vicinityof the underside of the moulding drum 16, there is a release device 24for releasing moulded products from the mould cavities of the mouldingdrum 16, as well as a discharge belt 26 beneath it. Via this dischargebelt 26, the products can be fed to other processing stations, forexample a protein-coating device, a freezing device or a packaginginstallation. The moulding device 10 also comprises a control unit 28for controlling the various components. With a view to making thedevice, in particular the moulding drum 16 and the mass feed member 18,accessible for maintenance and cleaning purposes, the mass feed member18 is secured to a subframe 30, which can be rotated about a pivot pin34 with the aid of a piston/cylinder assembly 32, so that the mass feedmember 18 can be moved out of a working position illustrated in FIGS. 1and 2 into an at-rest position (not shown) at a distance from themoulding drum 16 after coupling 36 between connecting pipe 22 and massfeed member 18 has been released.

In the embodiment shown in FIG. 3 a) and b), rectangular recesses 42 areprovided in the outer circumference 40 of the moulding drum 16, which isin this case hollow. Exchangeable inserts 44 of corresponding dimensionscan be secured in these recesses 42.

For this purpose, bores 46 are provided at the corners of an insert 44,aligned with threaded holes 47 in the base 48 of the recess 42, andbolts 50 can be fitted into them. In the base 48 of a recess 42 there isan opening 52 which is in communication, via one or more axialconnecting passages and distribution device (not shown), with an opening54 in an end piece 56 of the moulding drum 16. This opening 54 is incommunication with excess-pressure means (not shown), such as acompressor, for supplying a forcing fluid via a flexible hose 57, andwith reduced-pressure means (not shown), for example a vacuum pump, viaa flexible hose 58. In its top side, the insert 44 comprises a mouldcavity 60 of a shape which corresponds to the shape of the product whichis to be produced.

In the embodiment shown in FIG. 4, the insert 44 together with spacer62, forms an assembly 64. Insert 44 comprises the mould cavity 60delimited by vertical walls 66 and base 68, while spacer 62 is a flatplate in which there is a through-opening 72, the dimensions of whichare larger than the mould cavity 60.

The insert 44 is made from a porous material, such as sintered steel.The pores are denoted by reference numeral 73. They open out in the base68 and peripheral wall 66. Therefore, in the assembled state, there is aspace between the underside of this insert 44 and the base 48 of therecess 42, this space also being delimited by the peripheral wall 74 ofthe opening 72 in spacer 62, which space is in communication with, onthe one hand, the pores 73 in the insert 44 and, on the other hand, theopening 52, so that during operation the mould cavity 60 can beefficiently evacuated, and during the release operation a forcing fluidcan be supplied between product and boundary. The insert 44 is arectangular body with a flat underside and sides, apart from the topside 75, which is curved. The radius of curvature of the curved upperside 75 is identical to the radius of curvature of the moulding drum 16.

FIG. 5 illustrates the way in which this embodiment of a device 10according to the invention operates. The mass which is to be moulded isforced into the mould cavity 60, which is in a filling position, via themass feed member 18, while air is being sucked out of this mould cavity60 through the pores in the insert 44 in question, the opening 52 and aconnecting passage 76 with the aid of reduced-pressure means. This mouldcavity 60 is filled during the rotation (direction of rotation indicatedby an arrow) of the moulding drum 16 past the filling position. As aresult of further rotation, a mould cavity 60 moves into a releaseposition where a moulded product 78, under the force of gravity, dropsout of the mould cavity 60 onto a discharge belt 26 moving beneath it.The release is assisted by supplying compressed air or other pressuremedium, for example water, to the mould cavity 60 via the connectingpassage 76 and the porous insert 44. The compressed air is supplied byexcess-pressure means (not shown).

FIG. 6 shows the latter aspect in more detail. From the connectingpassage 76, compressed air is passed through the opening 52 in the base48 of the recess 52 in the drum 16 into distribution space 82, fromwhere the compressed air (indicated by arrows) forces its way throughthe pores in the boundary of the insert 44 and expels a product.

For the sake of simplicity, FIG. 3-6 in each case illustrate acombination of excess-pressure means and reduced-pressure means.

As will be clear from the general description given above, the twoaspects can also be employed separately.

FIG. 14 shows an embodiment of a mould cavity 60 with a permeableboundary with a complete pore structure for the base 68 and peripheralwall 66. In addition to the pores 73, passages 200 are provided in thebase 68. In the situation illustrated, the pores 73 are fed with agaseous forcing fluid, such as compressed air, via a separate feed 202.The passages 200 are provided with a liquid forcing fluid, such aswater, via a separate feed 204. As an alternative to a separate supply,it is also possible to use a mixture of liquid and gaseous forcingfluids.

FIG. 15 shows yet another embodiment, in which the boundary of a mouldcavity 60 is of layered structure. An innermost boundary layer 206comprises a pore structure, while the outermost boundary layer 208 isprovided with passages 200. A forcing fluid is introduced into adistribution chamber 212 via feed 210. From there, the fluid flowsthrough the passages 200 and then via the pores 73 and into the mouldcavity.

FIGS. 16 and 17 show two different pore structures. One is composed ofsintered, substantially round metal grains (FIG. 16) and one is composedof sintered, irregularly shaped metal particles. In the case of the porestructure shown in FIG. 17, the risk of a meat mass or small pieces ofmeat sticking in the pores is lower than in the case of the structureshown in FIG. 16, since the depth of penetration of the mass is lower onaccount of the relatively high resistance caused by the irregular natureof the pores.

FIG. 18 shows a boundary part with irregular passages 200 which taperfrom the outside towards the mould cavity 60.

FIG. 19 shows a boundary of a mould cavity 60 in which the boundarycomprises a coating layer 220 which is given a surface charge by areversible chemical reaction, repelling the oppositely charged particles(indicated as dipoles) from the product starting material.

FIG. 20 illustrates a method in which an additional electromagneticrepulsion force is generated in order to release a product from themould cavity 60 with the aid of an electromagnet 222.

FIG. 7 shows another embodiment of a moulding device 10 according to theinvention, in which components which correspond to those shown in FIG.1-6 are denoted by the same reference numerals. The moulding drum 16comprises recesses 42 which are distributed over its circumference andin which a filler piece 81 is positioned. In this case, the mould cavity60 is delimited by the top side 83 of filler piece 81 and side walls 84of the recess 42. The top side 83 in this case has a surface which isprovided with a contour, so that an attractively shaped appearance canbe imparted to the product. The mould cavities 60 of the moulding drum16 can once again be selectively coupled to either reduced-pressuremeans or feed means, as described for a different embodiment withreference to FIGS. 5 and 6. For this purpose, an opening 52, which isaligned with bore 85 in filler piece 81, is provided in the base 48 ofthe recess 42. A web or strip 86 is wound around the moulding drum 16.This strip 86 has a sandwich structure and comprises an upper layer 88made from a plastics material, in which flexible premoulds 90 areprovided, substantially corresponding to a mould cavity 60, and a lowerlayer 92, which during operation is in contact with the outercircumference of the moulding drum 16 and is made from a more rigidmaterial, in which there are round openings 94, the diameter of which inthis case substantially corresponds to that of the premoulds 90 andtherefore to that of the mould cavities 60. The two layers 88 and 82 areconnected to one another in a suitable way. One end 96 of the web 86 ofa sandwich structure is provided with securing means which interact withsecuring features on the drum 16. An example is a row of small openings98 which are positioned over short projections on the drum 16.

The free end 102 of the web may be fixed to the drum 16 or to itself,for example using adhesive tape or the like. To protect the web 86,there is a wear-resistant material, for example stainless steel,protective strip 104, in which openings 106 which likewise correspond tothe flexible premoulds are provided. One end of the protective strip 104has a flanged edge 108 which, during operation, engages in an axialgroove 110 provided in the outer circumference of the drum 16. The otherend 112 has spring securing means 114 at its corners, and these meanscan be fixed to projections on the drum 16, so that the protective strip104 can be clamped taut around the drum 16 and in this way also holdsthe flexible strip 86 beneath it in place.

During operation, at the filling position the flexible premoulds 90 inthe mould cavities 62 are filled with mass or a portion of mass, itbeing possible for the air which is present beneath the flexiblepremould 90 in the mould cavity 60 to be sucked out, for example via thecentral bore 85 in filler piece 81 and opening 52 connected to it in thebase 48 of recess 42, which opening can be connected to reduced-pressuremeans via an axial connecting passage in the manner described above. Atthe release position (FIG. 8), the flexible premould 90 is pushed out ofthe mould cavity 60 with the aid of compressed air, which is led to themould cavity 60 in the manner which has likewise already been described,and the moulded product 78 can be released, if desired with theassistance of a release device, for example a spindle belt which is tobe described below.

The release device 24 shown in FIG. 8-10 is arranged beneath themoulding drum 16 at the release position and in the situationillustrated comprises an endless conveyor. This conveyor comprises twoendless chains 120 which are arranged parallel to one another and areguided in a fixed path over toothed wheels 122. Toothed wheels 128arranged on a common driven axle 126 engage in the vicinity of thecentre of a top part 124, moving towards the drum 16, of the conveyor. Adrive unit is denoted overall by reference numeral 130. The links 132 ofthe chains 120 (cf. FIG. 10) are lengthened on the inner side by anextension piece 134 which projects inwards. Extension pieces 134 ofcorresponding links 132 of the two endless chains 120 are connected toone another by thin transverse spindles 136, in such a manner that thetransverse spindles 136, at the reversing point, pass through the centreof the axis of the toothed wheel 122 in question. This results in theformation of a pointed nose which is responsible for further removingmoulded products 78 from the mould cavity 60.

FIG. 11 diagrammatically depicts an embodiment of a mass feed member 18,in which identical components are once again denoted by identicalreference numerals. The mass feed member 18 comprises a virtuallysemicircular housing 140 with a through- passage 142 extending in theradial direction (cf. also FIG. 13) with an inlet 144 for the mass whichis to be moulded from a storage device 19 and an outlet 146 for the massto pass to a mould cavity 60. Side walls 148 and 150 of the housing 140are provided with openings 152 extending in the radial direction.

Radially movable lamellae 154, for example made from metal, are arrangedbetween corresponding openings 152 in the side walls 148,150. Thecentral part of the mass feed member 18 comprises a filler block 156which is fixedly connected to the housing and in which thethrough-passage 142 is provided. That side of the mass feed member 18which faces towards the moulding drum 16 comprises a plate 158 made froma flexible plastic, for example Teflon, in which the outlet 146 to amould cavity 60 is provided. Between the inner wall of the housing 140and the lamellae 154 there is a pressure cushion 160 which can bepressurized using a suitable pressure medium, such as compressed air orpressurized water or other liquid. In this way, during operation, theTeflon plate 158 is pressed onto the moulding drum 16 in such a manneras to form a seal, the lamellae 154 forming a large number of ribs whichextend in the axial direction of the moulding drum 16 and impart therequired rigidity, while the Teflon plate 158 is able to adapt topossible deviations in the radius of the moulding drum 16. On one sideof the through-passage 152 there is a cutting blade 170 for cuttingthrough tough pieces, such as muscle fibres.

In the embodiment of the moulding drum 16 illustrated in this figure,there are provided, in its outer wall, recesses 42 which have a widenedbase 162, extend in the longitudinal direction and into whichcorresponding inserts 44 with a mould cavity 60 can be pushed from thecorresponding end of the moulding drum 16.

FIG. 21 shows a perspective illustration of an exchangeable mouldingdrum 16 as an embodiment of a moulding surface according to theinvention. The moulding drum 16, which can rotate about an axle 250,comprises a cylindrical drum wall 252.

The outer side of the cylindrical drum wall 252 comprises recesses 42.In each recess 42 there is an insert 44, which insert 44 comprises amould cavity 60 which is defined by a boundary provided with holes,namely walls 66 and base 68. In the embodiment illustrated, all themould cavities 60 are identical in shape. It is also possible for theshape of the mould cavities to differ, for example for each annulardrum-wall part to have identically shaped mould cavities, while theshape of the mould cavities differs from one annular drum-wall part toanother. It is therefore relatively easy to make a range of products ofdifferent shapes and then package these products.

FIG. 22 shows a moulding drum similar to that shown in FIG. 21, exceptfor the fact that the exchangeable inserts 44 are elements which extendin the longitudinal direction of the drum and are each provided withfour mould cavities 60.

FIG. 23 shows a particularly preferred embodiment of a moulding drum 16according to the invention which can be exchanged in its entirety. Themoulding drum 16 comprises a piece of porous metal, the surface pores ofwhich have been sealed at the outer surface and the inner surface. Themould cavities 60 are formed by spark erosion, with the result that theboundary, comprising base 68 and side walls 66, has acquired the porousstructure, since the pores are uncovered as a result. It is easier toreplace one moulding drum with another than to exchange the removableinserts as used in the embodiments shown in FIGS. 21 and 22.

1-62. (canceled)
 63. A moulding device for moulding three-dimensionalproducts from a meat mass suitable for consumption, comprising: arotatable moulding drum having a longitudinal axis and axial ends, saiddrum comprising: a cylindrical drum wall having an outer peripheralcylindrical surface, multiple mould cavities formed in the outerperipheral surface of the drum wall, which mould cavities define theshape of the products which are to be produced, the mould cavities beingopen on one side and defined by a boundary comprising walls and base, adrum drive, adapted to rotate the rum in a direction of rotation aboutthe longitudinal axis thereof, a mass feed member arranged at a massfeed position along the outer peripheral cylindrical surface of themoulding drum and adapted to feed said mass to passing mould cavities,which mass feed member comprises: a housing with an inlet side and adrum side which faces the drum, a through-passage provided in thehousing for the mass of foodstuff to pass from an inlet towards anoutlet located on the drum side, a flexible plate located at the drumside of the housing in which the outlet to a mould cavity is provided,extending on either side of the outlet over a distance which covers atleast one mould cavity, a pressure medium operated excess-pressuremeans, arranged between the drum side of the housing and the flexibleplate over a distance which essentially covers said flexible plate, saidexcess-pressure means being adapted to apply a pressure onto saidflexible plate to flexibly bear the plate in sealing engagement againstthe outer peripheral cylindrical surface of the drum, to adjust in asealing manner to irregularities in the outer peripheral cylindricalsurface of the drum.
 64. Moulding device according to claim 63, whereinthe pressure medium is compressed air or pressurized water or otherliquid.
 65. Moulding device according to claim 63, wherein theexcess-pressure means comprise at least one pressure cushion. 66.Moulding device according to claim 63, wherein the flexible plate ismade from a flexible plastic, for example Teflon.
 67. Moulding deviceaccording to claim 63, further comprising a pressurized fluid feedmember in fluid communication with the boundary of a mould cavity andfurther excess-pressure means for supplying a pressurized fluid, whichpressurized fluid feed member is adapted to apply the pressurized fluidfor eliminating adhesion forces between the boundary of a mould cavityand a moulded product, to assist the removal of moulded product from theone or more mould cavities at a product removal position along the outerperipheral cylindrical surface of the moulding drum.
 68. Moulding deviceaccording to claim 63, further comprising reduced pressure means forforming a reduced pressure in the mould cavities, the boundary of themould cavities at least in part being provided with a large number offine openings which are in communication with the reduced-pressuremeans.
 69. Moulding device according to claim 67, further comprisingreduced pressure means for forming a reduced pressure in the mouldcavities, the boundary of the mould cavities at least in part beingprovided with a large number of fine openings which are in communicationwith the reduced-pressure means.
 70. Moulding device according to claim67, further comprising an end piece at one of the axial ends of the drumand wherein a fluid communication is formed by a connecting passage incommunication with the boundary of a mould cavity and an opening in saidend piece of the drum.
 71. Moulding device according to claim 68,further comprising an end piece at one of the axial ends of the drum andwherein a fluid communication is formed by a connecting passage incommunication with the boundary of a mould cavity and an opening in saidend piece of the drum.
 72. Moulding device according to claim 67,wherein the pressurized fluid feed member comprises an air compressoradapted to provide pressurized air to the distribution channel of mouldcavities that arrive at the product removal position.
 73. Mouldingdevice according to claim 63, wherein the moulding device furthercomprises a discharge belt arranged beneath the drum to receive productsdropped from mould cavities passing a product removal position above thedischarge belt.
 74. Moulding device according to claim 63, wherein themould cavities are distributed about the drum wall in peripheraldirection and in a direction of rotation of the drum.
 75. Mouldingdevice according to claim 63, wherein the boundary of the mould cavitycomprising a porous plastic or porous sintered metal forming a porousstructure of intercommunicating pores opening out in said one or moremould cavities.